SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9dc406d7cc20d942367528d0564934e5a3b7757b5b367c52e5ec5ff775a9b382' 
  AND token = '36j9xcebWXHcv2Q8yxSPOtczQXMZyPf0+n/KqTKsvJY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}